diff --git a/19_observability/19.3_performance_optimization.md b/19_observability/19.3_performance_optimization.md
index b50a9c8..43877c5 100644
--- a/19_observability/19.3_performance_optimization.md
+++ b/19_observability/19.3_performance_optimization.md
@@ -510,7 +510,7 @@ WORKDIR /build
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     build-essential \
-    && rm -rf /var/apt/lists/*
+    && rm -rf /var/lib/apt/lists/*
 
 COPY requirements.txt .
 RUN pip install --user --no-cache-dir -r requirements.txt